title: Tissue coverage and neointimal hyperplasia in overlap versus nonoverlap segments of drug-eluting stents 9 to 13 months after implantation: in vivo assessment with optical coherence tomography.
abstract: BACKGROUND
  Histologic experimental studies have reported incomplete neointimal healing in overlapping with respect to nonoverlapping segments in drug-eluting stents (DESs), but these observations have not been confirmed in human coronary arteries hitherto. On the contrary, angiographic and optical coherence tomography studies suggest that DES overlap elicits rather an exaggerated than an incomplete neointimal reaction.
  
  
  METHODS
  Optical coherence tomography studies from 2 randomized trials including sirolimus-eluting, biolimus-eluting, everolimus-eluting, and zotarolimus-eluting stents were analyzed at 9- to 13-month follow-up. Coverage in overlapping segments was compared versus the corresponding nonoverlapping segments of the same stents, using statistical pooled analysis.
  
  
  RESULTS
  Forty-two overlaps were found in 31 patients: 11 in sirolimus-eluting stents, 3 in biolimus-eluting stents, 17 in everolimus-eluting stents, and 11 in zotarolimus-eluting stents. The risk ratio of incomplete coverage was 2.35 (95% CI 1.86-2.98) in overlapping versus nonoverlapping segments. Thickness of coverage in overlaps was only 85% (95% CI 81%-90%) of the thickness in nonoverlaps. Significant heterogeneity of the effect was observed, especially pronounced in the comparison of thickness of coverage (I(2) = 90.31).
  
  
  CONCLUSIONS
  The effect of overlapping DES on neointimal inhibition is markedly heterogeneous: on average, DES overlap is associated with more incomplete and thinner coverage, but in some cases, the overlap elicits an exaggerated neointimal reaction, thicker than in the corresponding nonoverlapping segments. These results might help to understand why overlapping DES is associated with worse clinical outcomes, both in terms of thrombotic phenomena and in terms of restenosis and revascularization.
authors.affiliation: Erasmus Medical Centre, Thoraxcentre, Rotterdam, The Netherlands.
authors.forename: Juan Luis
authors.initials: JL
authors.lastname: Gutiérrez-Chico
authors.forename: Lorenz
authors.initials: L
authors.lastname: Räber
authors.forename: Evelyn
authors.initials: E
authors.lastname: Regar
authors.forename: Takayuki
authors.initials: T
authors.lastname: Okamura
authors.forename: Carlo
authors.initials: C
authors.lastname: di Mario
authors.forename: Gerrit-Anne
authors.initials: GA
authors.lastname: van Es
authors.forename: Stephan
authors.initials: S
authors.lastname: Windecker
authors.forename: Patrick W
authors.initials: PW
authors.lastname: Serruys
mesh_terms: D023903:Coronary Restenosis / Q000175:diagnosis / Q000517:prevention & control; D023921:Coronary Stenosis / Q000473:pathology / Q000601:surgery*; D003331:Coronary Vessels / Q000473:pathology*; D054855:Drug-Eluting Stents; D000068338:Everolimus; D005240:Feasibility Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D006965:Hyperplasia; D007166:Immunosuppressive Agents; D008297:Male; D008875:Middle Aged; D058426:Neointima / Q000473:pathology; D011474:Prosthesis Design; D020123:Sirolimus / Q000031:analogs & derivatives / Q000494:pharmacology; D013997:Time Factors; D041623:Tomography, Optical Coherence / Q000379:methods*; D016896:Treatment Outcome
chemical_list: D007166:Immunosuppressive Agents; D000068338:Everolimus; C489443:zotarolimus; D020123:Sirolimus